This paper studies and defines the concept of contribution as special types of taxes which are are imposed on the salary of employees for a specific purpose. The Contribution Act prescribes the obligation to pay contributions for funding of compulsory insurance. The term contributions for compulsory insurance includes: compulsory pension insurance based on generational solidarity, compulsory pension insurance based on individual capitalized savings and compulsory health insurance. Various examples show their usage and calculation in practice. The aim of this paper is to show how contributions are calculated in different cases in the Republic of Croatia in 2020. All necessary official JOPPD forms and calculation tables were used to create examples, as well as the applicable laws and regulations that are currently in force. This paper distinguishes various situations with calculations of contributions which are paid, limited or released. These examples relate to contributions to secondary income and compulsory insurance of board members. Therefore, this paper distinguishes situations in which there is exemption from contribution obligations tosecondary income and those in which there is no exemption from contribution obligations, and members of the management board who are in the compulsory insurance system and outside the compulsory insurance system. The basic segment for the calculation of contributions is the average gross salary paid to employees of legal entities in the Republic of Croatia from January to August last year, and the corresponding coefficients. The average gross salary in 2019 is HRK 8,742.00.